Variable speed phonomotor



Sept. 6, 1955 SABURO AKAl VARIABLE SPEED PHONOMOTOR Filed Dec. 12, 1951 0 25 T 7. W m 9U j m m INVENTOR.

4 fiaf/vrfof United States Patent VARIABLE SPEED" PH'oN'oMoroR Saburo Akai, Ohta-ku, Tokyo, Japan Application December 12, 1951, Serial No. 261,305 Claims priority, application Japan August 9', 1951 3 Claims. (Cl. 74-194) This invention relates to a variable speed phonomotor.

One object of the invention is to provide a variable speed phonomotor which is in its construction very compact, rigid and simple.

Further object is to provide a variable speed phonomotor which is in its assembly or construction very convenient for mass production.

Further object is to provide a phonomotor of this kind which is as a whole unit substantially balanced in weight, and therefore, free of noisy sound which is caused by quaking of the unit.

Further object is to provide a phonomotor of the kind referred to in which a friction gear is employed for attaining variable speed of rotation of the turn-table shaft correctly.

Further objects and advantages to be brought about by the invention will be described with reference to the accompanying drawings illustrating the embodiment of the invention.

Of the drawings, Fig. 1 is a plan view of the phonomotor of the invention with an operating handle, Fig. 2

a side view of same as seen from the right hand side, Fig. 3 a transverse section through Fig. 1, Fig. 4 an inside view of a main half case, and Fig 5 a similar view of an auxiliary half case, both the main and auxiliary half cases being adapted to be combined together to form an enclosed box.

Referring to the drawings, 1 is the main half case, adapted to be combined with the auxiliary half case 2 by means of screw holes 3 for insertion of bolts so as to form a unit box of phonomotor.

According to the invention the main and the auxiliary half cases 1 and 2 are separately constructed, each containing necessary elements therein, and subsequently they are assembled or combined together to form an enclosed, tight and compact box for the phonomotor.

In the main half case 1 there is installed a fixed iron core 4 of an electric motor, which has a rotor axle 5, provided with a worm gear 6, which is adapted to engage a worm wheel 7, fixed to a shaft 8, which is at one end supported by a spring 9 through the intermediary of a spherical roller 10. The resilient force of the spring 9 can be adjusted by means of an adjusting nut 11. Fixed to the shaft 8 there is also a friction disc wheel 12, which functions as hereinafter described. The shaft 8 is at the other end pivoted on a bridge piece 13, fixed suitably to the main case 1. It is noted that all the elements above described are accommodated within the main case 1.

Next, the auxiliary case 2 is constructed as follows. Vertically disposed within the auxiliary case 2 there is a rotary shaft 14, the one end of which projects outwardly of the case 2, forming a supporting part for the turntable of a phonograph. The rotary shaft 14 carries fixed thereon a sliding wheel 15, which is provided with an encircling friction band 16 made of leather, hard rubber, synthetic rubber or the like. The sliding wheel 15 is so arranged as to be slidable by means of a key 19 engaging in a groove formed in the shaft 14, but nonrotatable by itself.

atlases Patented Sept. 6, 195 5 The boss 17 of the sliding wheel is formed with a groove 18 for reception of pins 21, which are fixed to an actuating'leverage' consisting of an angled piece 20 and a U-shaped piece 20, of which the two extremities carry the pins 21. The angled lever 20 is pivoted on the angled part by a pivot 22, and has bifurcated ends 20'.

Vertically extending also through the case 2 there is an operating rod 24, one end of which projects out of the case 2. Within the case 2 the rod 24 has fixed thereon a stud 25. Pivoted to the angled bar 20 there is a spring urged, right-angled pressing piece 23, which urges the stud firmly against one of the bifurcated ends 20", thereby constantly securing a firm grip between them. The operating rod 24 is at its upper portion supported by a plate spring fixer at 26, which spring urges the rod 24 firmly toward the inner recessed portion of the case 2.

The projected part of the rod 24 is cut off so as to form a slightly rectangular form, and adapted to engage a speed varying handle 28, provided with bifurcated ends 29, which are tightened or released by a screw 30. The other end of the handle 28 is provided with a needle 31, which is adapted to point to a scale plate 32 with graduations 33. It is, of course, understood that the operating handle and scale plate are disposed on the cover plate of a phonograph, as generally known in the art. The reference 34 is an adjusting knob for the rotor axle 5 and its related parts.

The operation of the device constructed as above is as follows:

The main and the auxiliary half cases 1 and 2 are joined together to form a unit as shown in Fig. l, and the electric motor is started, then the rotation of the rotor axle 5 is transmitted through the worm gear 6 and the worm wheel 7 to the friction disc wheel 12, which is, in the assembled position shown in Fig. 1, in a frictional engagement with the sliding wheel, and therefore causes now the sliding wheel 15 and consequently the rotary shaft 14 to rotate. The variable speed of the rotary shaft 14 may according to the invention be obtained by means of the operating rod 24. That is, the actuation of the handle 28 in one or other direction along the scale plate 32 causes the rod .24 to revolve and in consequence thereof the leverage consisting of 20 and 20 is displaced accordingly under the gripping action of the stud with the bifurcated end 20", and hence the pins 21 carried on the extremities of the U-formed lever 20' are displaced so as to let the sliding wheel 15 slide vertically to either side along the length of the shaft 14. This sliding axial movement results in the variation of the engagement point of the sliding wheel 15 with the friction disc wheel 12. The closer the engagement point is to the centre of the friction disc wheel, the slower is the 1 rotation speed of the shaft 14, and when an extremely brought to a standstill.

inner point of engagement is attained the shaft 14 is On the contrary, the further the engagement point is from the centre of the friction disc wheel 12, the faster becomes the rotation speed of the shaft 14. In this way, the variable speed of rotation of phonomotor is realized.

According to the invention, by adopting the unique assemblage the construction of the phonomotor is extremely simplified. The main and auxiliary half cases 1 and 2 can be constructed separately, thereby simplifying considerably the assembly of the phonomotor, and as a consequence thereof a mass production of same can be realized economically and easily. The elements contained in the half cases 1 and 2 were respectively selected for attaining a substantial balance of weight when they will be assembled together to form a unit box of the phonomotor. This secures a very stable support of the unit box to the cover plate of a phonograph, thereby eliminating the quaky sounds occurring in this kind of phonomotor.

According to the invention the'friction gear adopted is of skillful arrangement, thereby securing a correct, smooth and unnoisy transmission of rotation.

I claim:

1. A variable speed phonomotor comprising main and auxiliaiy half cases so formed as to be combined together to form a unit box, the main half case containing a motor having a rotor axle provided with a worm gear, a worm wheel supported to engage the worm gear, and a friction disc wheel mounted to rotate with the worm wheel, and the auxiliary half case containing a rotary shaft, a wheel axially slidable but non-rotatively mounted on the rotary shaft, an operating rod operable from outside, a boss on the slidable wheel, leverage having pins engaging a groove formed in the boss of said slidable wheel and which has bifurcated ends to engage a stud fixed on the operating rod. said slidable wheel being positioned to frictionally engage said friction disc wheel when the half cases are joined together so that actuation of the leverage through the operating rod varies the engagement point of the sliding wheel with the friction disc wheel to thereby control the speed of rotation of said rotary shaft.

2. A variable speed phonomotor as claimed in claim 1, in which the worm wheel and friction disc wheel arranged in the main half case are urged as a unit by a spring-pressed spherical roller to retain engagement between the friction disc wheel and slidable wheel, the resilient force of said ball being adjustable by means of an adjusting nut.

3. A variable speed phonomotor as claimed in claim 1, in which the leverage comprises a U-shaped piece carrying said pins adapted to engage in the groove formed in the boss of the sliding wheel, and a pivotally mounted angle piece extending from the U-shaped piece and provided with said bifurcated ends engaging said stud fixed on the operating rod, and a springpressed rightangled lever which is pivoted to the angled lever so as to press the stud toward one of the bifurcated ends, thereby securing a firm gripping of the last mentioned two members.

References Cited in the file of this patent UNITED STATES PATENTS 683,773 Kiger Oct. 1, 1901 1,229,401 Black et a1. June 12, 1917 1,434,814 Gray Nov. 7, 1922 2,218,651 Lenney Oct. 22, 1940 

